The role of three viral glycoproteins, gB, gC and gD in inducing humoral and cell-mediated immune responses in mice will be analyzed genetically and immunologically with wild-type HSV-1 (KOS) and mutants for the three glycoproteins. Two types of mutants will be sought: (1) Mutants that are deficient in the expression of one or a combination of the three glycoproteins, induced by in vitro mutagenesis of cloned restriction enzyme fragments; and (2) Mutants that express functional glycoproteins altered in primary structure, selected as resistant to neutralization by monoclonal antibodies against the glycoproteins, monoclonal antibody resistant mutants, mar mutants. Mutants will be mapped by genetic recombination and marker rescue techniques and characterized biochemically and immunologically. Immune responses will be induced in mice by infection with wild-type virus and by immunization with wild-type and a battery of mutant infected cells expressing the various subsets of three glycoproteins. A selected number of immune reactions will be monitored. For the humoral response, these will include virus neutralization, complement-mediated immune cytolysis, total antibody production by ELISA assay and quantitation of antibody forming cells. In testing for the cell-mediated response, assays of cytotoxic T lymphocytes and T cell proliferation will be used. The battery of mutant infected cells will be used as reactants in the in vitro assays to identify which of the glycoproteins are most active in inducing particular immune responses, that is, which are immunodominant. Evidence for interactions between the immunogens in inducing specific immune responses may emerge. In addition, genetic and immunological analyses of mar mutants with libraries of monoclonal antibodies will be used to (1) identify the predominant antibody specificities generated in the immune response to HSV-1, (2) estimate the number of antigenic determinants in a glycoprotein and (3) genetically map mutations affecting determinant sites and the immunogenicity of the glycoprotein. Finally, syngeneic mouse cells, transformed with the structural genes for single glycoproteins will be sought and used as unique material for immunization.